This application relates to placing economizer injection ports through the wrap of one of the scroll members in a scroll compressor.
Scroll compressors are becoming widely utilized in refrigerant compression applications. As known, a pair of scroll members have a base with a generally spiral wrap extending from the base. Typically, one scroll is non-orbiting and the other scroll orbits relative to the non-orbiting scroll. The orbiting scroll wrap contacts the non-orbiting scroll wrap to seal and define compression chambers. The compression chambers are moved toward a central discharge port as the orbiting scroll completes its orbiting cycle. Originally scroll compressors tended to have relatively thin wraps. More recently, so called xe2x80x9chybridxe2x80x9d wraps have been developed wherein the thickness of the wrap varies along its length.
Refrigerant systems are also making increasing use of an economizer cycle in which an additional heat exchange process occurs and a portion of the refrigerant is directed back to the compressor. At an intermediate point in the compression cycle, this refrigerant is injected into the compressor compression chambers through an economizer line and then into internal injection ports. This has the effect of increasing both system capacity and efficiency. The scroll compressor designer seeks to locate the internal injection ports to maximize the efficiency and capacity benefits as mentioned above.
The economizer ports have been formed through the base of the non-orbiting scroll penetrating into the compression chambers. Typically, the injection has occurred through economizer injection ports at a point in the compression cycle when the refrigerant is sealed off from suction to define a first compression chamber. After the seal off point, the injection ports continue to communicate with the compression chambers for a significant period of the cycle. Thus, the pressure within the compression chamber while initially relatively low soon increases. This increase in pressure inside compression chambers results in refrigerant being pumped back into the economizer line. This produces so called pumping losses, and hence decreased compressor efficiency which is undesirable.
In a disclosed embodiment of this invention, economizer fluid is injected into the compression chambers through ports formed within the wrap of one of the two scroll menibers. Most preferably, the injection ports are formed through the wrap of the non-orbiting scroll, which is most preferably of a xe2x80x9chybridxe2x80x9d profile such that it has varying thicknesses along its length.
The scroll member, which does not receive the injection ports in its wrap, has small grooves formed in the floor of its base plate. When the port is aligned with these grooves, economizer flow is injected into the compression chamber. However, once the orbiting scroll has moved such that the port is no longer aligned with the groove, the facing base plate closes the port off. In this way, the scroll compressor designer is able to easily control the xe2x80x9con/offxe2x80x9d time for the economizer injection into the compression chamber. The grooves can be formed at a location such that the economizer ports are closed prior to the occurrence of significant pumping losses. Stated another way, the grooves can be formed such that the economizer injection port is open for a short period of time, and such that there is no back flow into the ports as the pressure inside the compression pockets increases.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
FIG. 1 is a schematic view of a refrigerant cycle incorporating a scroll compressor and an economizer cycle.
FIG. 2A is a front view of the non-orbiting scroll of the present invention.
FIG. 2B is a view of the rear face of the non-orbiting scroll.
FIG. 3 shows the front face of the orbiting scroll.
FIG. 4A shows one point in the cycle of the inventive scroll compressor.
FIG. 4B shows a subsequent point.
FIG. 4C shows yet another subsequent point.